Pulse group system of communications



April 8, 1952 c. E. cLEEToN PULSE GROUP SYSTEM OF COMMUNICATIONS HEETs-SHEET i Filed OCb. 1l, 1940 April 8, 1952 c. E. cLEl-:TON

PULSE GROUP SYSTEM OF COMMUNICATIONS 2 SHEETS-SHEET 2 Filed Oct. 11, 194C AMAAM MAMMA vvvvvvvv I l S Annu vuvvvv C'aud E. Cleei'orz m l lll Sw Hull W |H||| lumi c n I ...1 N S A L m mm m M M Y SIW Mw W W u m MF M s v 'l v v lvkvm .un

AMMAA "nur TTORN Patented pr. 8, 1952 UNITED STATES PATENT OFFICE PULSE GROUP SYSTEM OF COMMUNICATION S 37 Claims.

amended April 30, 1928; 370 0. G. 757) This invention relates to a system of communication in which the dots and dashes of conventional telegraphic code, hereafter termed signal elements, are transmitted by groupsof pulses 'at the beginning and end of each signal element.

It is an object of this invention to provide rmeans for transmitting a predetermined arrangement of pulses at the beginning oi a signal element and then another arrangement at the end 'of such element.

It is also an object of this invention to provide receiving means that will respond to the group of pulses denoting the beginning of a signal element by starting an audio or other discernible signal indication and terminate the same 'upon reception of the pulse arrangement marking the end of the signal element.

The foregoing and other objects are realized by the apparatus shown in the drawings wherein:

Fig. 1 is a schematic diagram of a transmitting system for sending two pulses at the beginning of a signal element and one pulse at the end thereof;

Fig. 2 is a schematic representation of a system whereby three pulses are sent at the beginning of a signal element and two pulses at the end thereof; and

Fig. 3 discloses a receiving circuit suitable for responding to the signals transmitted by apparatus as shown in Fig. l.

The system disclosed herein has a great advantage over the conventional system of transmitting code in that the peak power during the -p'uls'es ymay be many times the average power the transmitter -is capable of handling continuously. This' increases the reliability of code transmission under poor transmitting conditions. Further, the present system requires no -special type of key and the duration of the signal element at the receiver is determined by the length of time the key of the transmitter is held closed Referring now to Fig. 1, the tubes 4 and E have their respective anodes 6 and 'I connectedito the positive plate supply 8 through respective kanode :resistors 9 and I0. The grids II and I2 are con- V-nected to negative bias lead I3 through resistors I4 and I5. The grid I I is also connected to anode 'I .through resistor I6 and capacitor I'I in parallel vvtheach other and grid I2 is likewise connected 'to' anode 6 through resistor I8 and capacitor I9 in parallel. Cathode 20 of tube 4 is connected to ground while cathode 2| of tube 5 is normally open circuited through the key 22.

Resistor I4 is two' or more times as great as resistor I5 and consequently the potentiometer eiect of resistors I8 and I4 is such that when key 22 is closed the tube 5 becomes conducting and tube 4 is made non-conducting but so long as the key 22 is open the tube 4 will conduct.

Tubes 23 and 24 are connected together to constitute a symmetrical or locked electronic relay. That is, when either of tubes 23 and 24 is conducting the other tube is held non-conducting until the conductivity conditions are changed by application of a voltage pulse from a source outside the relay itself. As hereinafter used, the term tript means to change the conductivity from the tube that is initially conducting to the one that is initially non-conducting while the term reset refers to the .reverse operation.

Tubes 23 and 24 are interconnected by resistor 25 and capacitor 26 in parallel between anode 21 and grid 28 and the similar connection of anode 29 to grid 30 through parallel connected resistor 3 I and capacitor 32.

The gaseous discharge device 33 is connected in parallel with capacitor 34 to anode 2l through the resistor 35. When tube 23 is non-conducting the capacitor 34 is charged through resistor 35 to the breakdown potential of tube 33 and thereupon the tube 33 becomes conducting and discharges capacitor 34 with the production of a negative pulse that is transmitted over lead 36 and through capacitor 3l to the grid 38 of tube 24.

The operation of this ysystem is as follows: Tube 4 is initially conducting due to the fact that key 22 is open, and tube 23 is also initially conducting. When key 22 is closed the unsymmetrical values of the circuits above described result in tube 5 becoming conductive while tube 4 is blocked by the potential drop across resistor I0 applied to grid II. The resulting rise of potential on anode 6 is transmitted through lead 38a and capacitor 39 to the grid 40 of amplifier tube 4I which is biased to cutoff. However, when the positive pulse is impressed upon grid 40 the tube 4I becomes momentarily conducting and the .resultant potential drop through anode resistor 42 is transmitted over lead 43 as a negative output pulse.

`Simultaneously with the :transmission of .the positive pulse to grid 40 a. negative pulse derived from the dropthrough resistor I0 is transmitted through capacitor 44 and lead 45 to grid 46 of tube 23, thus tripping this relay and causing tube 24 to become conductive. Capacitor 34 then charges up until the breakdown potential of tube 33 is reached when it discharges and a negative pulse is transmitted through lead 36 and capacitor 31 to grid 38 of tube 24 which resets this relay. When the conductivity is thrown from tube 24 back to tube 23 the potential on anode 29 rises to substantially supply voltage and a positive pulse is transmitted through lead 41 and capacitor 48 to vthe grid 49 of tube 55, causing tube 50 to become transiently conductive and thereby giving rise to a negative pulse in the common output 43. The time interval between the two negative pulses thus produced when the key 22 is closed may be controlled by the values of capacitor 34, resistor and the potentials applied to-the tube 33.

When key 22 is opened the potential on anode 1 rises to substantially supply voltage and a positive pulse is applied through lead 5l and capacitor 52 to grid 45 of tube 50 which causes a negative pulse in the output 43. It is thus apparent that with the system disclosed in Fig. 1 two pulses are transmitted when key 22 is closed and one pulse when key 22 is opened. It is of course underu .stood that the output from 43 may be used in any manner known to the art to cause the radiation of pulse signals.

Fig. 2 depicts a diierent embodiment of my invention whereby three pulses are produced upon closing the key and two pulses when the key is opened. The tubes 4 and 5 and the circuit elements interconnecting the same are the same as the correspondingly designated parts in the unsymmetrical circuit portion of Fig. 1, and con-sequently they will not be described again in detail. Likewise, the gaseous conduction device 33, capacitor 34 and resistor 35 are structurally and functionally the same as the like numbered elements in Fig. 1.

However, in Fig. 2 there are two symmetrical relays 53 and 54 and in each relay either tube, after being made conductive, continues to conduct until interrupted by the application of a negative pulse from an outside source. Initially, tubes 4, 55 and 51 are conducting. When key 22 is closed a negative pulse is applied to grid 58 of tube 55 which trips the relay and blocks tube 55 while making tube 55 conductive. The rise of potential on anode 59 of tube 55 is transmitted through capacitor 6D to an amplier that responds to positive pulses only and gives a negative pulse output, as above described in connection with tubes 4l and in Fig. l. Capacitor 34 then charges up and discharges through 33 which applies a negative .u

pulse through capacitor 64 to grid 6i of tube 51 and trips the relay 54 with a resulting rise in positive potential on anode 62 of tube 51 that is transmitted through capacitor 63 to the output ampliner.

Tube being still non-conducting the capacitor 34 charges again and upon discharge through tube 33 a negative pulse is transmitted through .capacitor 65 to grid 66 of tube 61 which resets relay 54 and throws conductivity back to tube 51. The resulting rise of potential on anode 68 is transmitted through capacitor 69 to the output .amplifier. Simultaneously, the drop in potential on anode 62 when tube 51 is again yrendered conductving transmits a negative pulse through capacitor conducts and the drop in potential on anode 6 'thereof is transmitted as a negative pulse over lead 12 and capacitor 13 to thegrid 58 of tube .55, .thus tripping relay 53 and the same negative pulse is transmitted through capacitor 14 to grid 5I of tube 51, thus tripping relay 54 also. There will be simultaneous positive pulses transmitted from tubes 55 and 51 through the respective capacitors 5i) and 53, to the output ampliers but since they are simultaneous they will give the effect of a single pulse from the output amplier.

Tube 55 being thus non-conducting, capacitor 34 will charge and, upon discharge through tube 33 will apply a negative pulse through capacitor 55 togrid 55 of tube 51. This resets relay 54 and the drop in potential on anode 62 of tube 51 is transmitted through capacitor 10 to grid 1I of tube 55 which resets the relay 53 and prevents further charging or" capacitor 34. When tube 51 is blocked by the negative pulse clue to the discharge of capacitor 34, the rise of potential on anode 55 is transmitted as a positive pulse through capacitor 55 to the amplifier. It is thus seen that two pulses are transmitted when key 22 in Fig. 2 is open.

It may be observed that grid 58 of tube .55 receives pulses from both plates of tubes 4 `and -5 and that these pulses are of opposite polarity. However, in practice relay 53 will trip due to the rise of a small grid leak to grid 53 and the fact that the output from tubes 4 and 5 is not balanced.

It will be obvious to those skilled in this art how additional symmetrical relays may be added to produce any desired number of pulses in the group at the beginning of a signal element and any diiierent number of pulses in the group .at the end of the signal element. The duration of the interval between the pulses marking the beginning of a signal element and the group denoting the end thereof is dependent entirely upon the time that the key 22 is kept closed.

Fig. 3 is a schematic showing of a receiver adapted to respond to signal elements defined by groups of pulses as above described. In particular, the circuit of Fig. 3 is adapted to receive communications transmitted by a system like that shown in Fig. 1, whereby two pulses are transmitted at the beginning of a signal element and one pulse at the end thereof. Relays 15 and 15 are of the symmetrical balanced circuit type above discussed. Grids 11 and 18 are respectively connected through capacitors 8| and 82 to the common input 83 and thus any negative pulse over input 83 will change the conductivity conditions in relay 15, blocking the tube that is conducting when the pulse is received and throwing conduction to the other tube in that relay. Initially tube 19 in relay i5 and tube 54 in relay 15 are conducting.

When the pair of pulses indicating the beginning of a signal element from the apparatus-of Fig. 1 is received through input 83, the ilrst negative pulse trips relay 15 and changes conductivity over to tube 85. Capacitor 85 does not reach the breakdown potential of tube 85 before the second pulse of the pair is received which is applied to grid 1B and resets relay 15. The rise in potential on anode 81 of 'tube 8U is transmitted 'as a positive pulse through :oapacitor 88 tothe grid 89 of tube .90 which is biased to cutoff by voltage divider 9| This positive pulse causes tube 9U to become transiently conducting and the potential drop across anode resistor 52 is applied as a negative pulse through capacitor 93 to grid e4 of tube A84 which trips relay 1S and causes tube S5 to become conductive.

The rise of potential on anode 95 of tube 84 Visapplied not only to vgrid 91 of.tube.95bu1:

also to grid 98 of tube 99. It will be seen that when tube 84 is conducting-the potential drop across anode resistor |00 will be applied to grid 91 of tube 95 and also, through lead |0| to grid 98 of tube 99, thus holding the tube 99 nonconductive and incapable of responding to an audio signal impressed on grid 98 through capacitor |02. However, when tube 84 is blocked the grid 98 of tube 99 rises to substantially the cathode potential and becomes conductive while relay 16 is tripped and thus makes perceptible in output |03 of tube 99 the audio signal impressed through capacitor |02. It is apparent that tube 99 will remain in operation during the interval between the two. pulses marking the beginning of a signal element and the singie pulse marking the end thereof, as will now be described.

When the single pulse denoting the end of a signal element is received it will trip relay '15, when was reset by the second pulse at the beginning of the signal element. This will start the capacitor 85 to charging and simultaneously the potential drop across anode resistor |04 will be applied through capacitor |05 and 'lead |06 to the grid |01 of tube 95 thus resetting `relay 1B, terminating the conductivity of tube 99 and ending the discernible signal output through capacitor |03. When capacitor 85 has reached the breakdown potential of tube 86 it will discharge through tube 86 and apply a negative pulse through capacitor |08 to grid '18 of tube 80 and reset relay 15. Likewise, the negative pulse will be transmitted through capacitor |09 to grid 89 of tube 90 and will neutralize the positive pulse applied to grid 89 through capacitor 88 due to the rise in potential of anode 81. tential applied to grid 89 is necessary to prevent tube 90 from becoming conductive and tripping relay 16.

It will be apparent that additional balanced relays may be added to respond to any selected number of pulses at the beginning of a signal element and at the end thereof. It is evident that the time of charging of capacitor 85 must be greater than the time between two successive pulses in a group to prevent resetting of relay 16 during reception of the first group of pulses, but it must be less than the time between successive signal elements in order that relay mayA be reset before the reception of the rst pulse of a new group.

The invention herein described and claimed may be used and manufactured by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim: l

1. A pulse group system of communication, comprising an unsymmetrical relay including a rst and a second tube each having an anode, a cathode and a grid; a common anode supply, a respective anode resistor connecting each said anode to said supply. grid returns including a respective grid resistor connected to each said grid, the said resistor connected to the grid of said second tube being at least substantially twice the value of the resistorconnected to the grid of said first tube, a resistor and a capacitor in parallel connecting the grid of each tube to the anode of the other, a key connected between the cathode of said second tube and ground to control the current path through said unsymmetrical re1ay;.a symmetrical relay including a third and This neutralization of the positive po- 6 a fourth tube each having an anode. a cathode, and at least two grids, respective anode resistors connecting the anodes of said third and fourth tubes to said anode supply, a capacitor connecting the anode of said second tube to trip said symmetrical relay on closing of said key to a first grid of said third tube; a gaseous discharge device having an anode, a cathode and a grid. a timing resistor connecting the anode of said device to the anode ofvsaid third tube, a charging capacitor connected in parallel with said device to be charged on tripping of said symmetrical relay, a capacitor connecting a first grid of said fourth tube to a point between said timing resistor and the anode of said-device to reset said relay on discharge of said capacitor through the gaseous dischange device; grid returns including a respective grid resistor connected toa second grid of each of said third and fourth tubes,a resistor and a capacitor in parallel connecting each said second grid to the anode of the other tube in the said symmetrical relay; two amplier tubes each having an anode, a cathode and a grid. a common anode resistor connecting the anodes of said amplifiers to anode supply, means connecting the cathodes of said amplifiers in parallel, a capacitor connecting the grid of one said amplifier to the anode of said first tube to deliver a rst pulse on closing said key, a respective capacitor connecting the grid of the other amplifier to the anode of said fourth tube to deliver a second pulse, when said symmetrical relay is reset and to the anode of said second tube to deliver a pulse when the key is released, and a common output connected to the anodes of both said amplifiers.

2. A pulse group system of communication, comprising an unsymmetrical relay including a iirst and a second tube each having an anode, a cathode and a grid; a common anode supply, a respective anode resistor connecting each said anode to said supply, grid returns including a respective grid resistor connected to each said grid, the said resistor connected to the grid of said second tube being at least substantially twice the value of the resistor connected to the grid of said rst tube, a resistor and a capacitor in parallel connecting the grid of each tube to the anode of the other, a key connected between the cathode of said second tube and ground;` asymmetrical relay including a third and a fourth tube, means interconnecting said third and fourth tubes whereby when one is conducting the other is held non-conducting, means to apply to said third tube pulses of potential due to changes in the anode potential of said second tube to trip said symmetrical relay on closing of said key; a gaseous discharge device having an anode, a cathode and a grid, a capacitor connected in parallelwith said devicetonbe charged on tripping of said symmetrical relay, a timing resistor connecting the anode of said device to said third tube to charge the capacitor in parallel with said de- .vice when said third tube is non-conducting,

means to apply to said fourth tube a negative pulse arising from discharge of said capacitor through said device to reset said relay; two amplifier tubes each having an anode, a cathode and a grid, a common anode resistor connecting the anodes of said amplifiers to anode supply, means connecting the cathodes of said amplifiers in parallel, a capacitor connectingthe grid of one said amplifier to the anode of said first tube to deliver ra first pulse on closing said key, a respec- ,tiveca-pacitor connecting the grid of the `other :amplifier-to the anode of said fourth tube to deliveria second pulse, `when said symmetricalrelay is reset and to the anode of said second tube to deliver a pulse when the key is released, and a common-outputconnected to the anodes of both said amplifiers.

3. A pulse group :system of communication, comprising an unsymmetrical relay including a first .and -a second tube each having an anode, a cathode vand a grid; a common 4anode supply,

azkeyaconnected .to break the circuit through said second tube when said key is open, means interconnecting .said tubes and said supply whereby said .first tube conductswhen said key is open and said second .tube alone conducts when .said key is closed; a symmetrical relay including a third and a fourth tube each having an anode, a cathode, and'at least two grids, respective anode resistors connecting the anodes of said third and fourth tubes to said anode supply, a capacitor connecting Ythe anode of said second tube to a irst grid of said third tube to trip said symmetri cal relay on closing of said key; a gaseous discharge device having an anode, a cathode and Ya grid, a timing resistor connecting the anode of .said device to the anode of said third tube, a

capacitor connected in parallel with said device to be charged .on tripping of said symmetrical relay, .a capacitor connecting a first grid of said fourth tube to .a point between said timing re sistor and the anode of said device to reset said relay on discharge of Vsaid capacitor through the gaseous discharge device; grid returns including a respective grid resistor connected to a second grid of each of said third and fourth tubes, a resistor and a capacitor in parallel connecting each saidsecond grid to the anode of the other tube in the said symmetrical relay; two amplifier tubes each having an anode, a cathode and a grid, a common anode resistor connecting the ranodes, of said amplifiers to anode supply, means connecting the cathodes of said amplifiers in parallel, a capacitor connecting the grid of one said amplifier to the anode of said iirst tube to deliver a rst pulse on closing said key, a respective capacitor connecting the grid of the other amplifier to the anode of said fourth tube to deliver a second pulse, when said symmetrical relay is reset and to the anode of said second tube to vdeliver a pulse when the key is released, and a common output connected to the anodes of both said ampliiiers.

4. vA .pulse Ygroup system of communication, comprising an unsymmetricai relay including a first and a second tube each having .an anode, a cathode and a grid; a common anode supply, a respective anode resistor connecting each said anode to said supply, grid returns including a respective grid resistor connected to each said grid, the said resistor connected to the grid of said second tube being at least twice the value of the resistor connected to the grid of saidflrst tube, a resistor and a. capacitor in parallel con-i necting the grid of each tube to the anode of the other, a key connected between the cathode of said second tube and ground; a symmetrical relay including a third and a fourth tube each having an anode, a cathode, and at least two grids, respective anode resistors connecting the anodes of said third and fourth tubes to said anode supply, a capacitor connecting the anode of said second tube to a first grid of said third 4tube to trip said symmetrical relay on closing of said key; 'agaseous discharge device vhaving an anode. a cathode and a grid, a timing resistor connecting the anode of said device to the anode of said third tube, a capacitor connected in parallel with said device to be charged on tripping of said symmetrical relay, a capacitor connecting a first grid of said fourth tube to a point between -said timing resistorand the anode of said device to reset said relay on discharge of said capacitor through the gaseous discharge device; grid returns .including a respective grid resistor connectedto a second grid of each of said third and fourth tubes, a resistor and a capacitor inparallel connecting each said second grid to the anode of the other tube in the said symmetrical relay; and Vmeans controlled severally by said first, said second ,and said fourth tubes to produce a negative output pulse upon cessation of conduction through any one of said first, second or third tubes.

5. A pulse group system of communication, comprising a first relay having two unsymmetrical conductive paths whereby one of said paths will conduct in preference to rthe other when both are closed, means operable to open or close said one path, said other path being initially conducting and said one path open; a second relay having two symmetrical conducting paths including means whereby either is held non-conducting while the other is conducting until the conductivity condition is changed by an applied potential pulse; means to derive a'negative'pulse from said one path in said first relay when said one path begins to conduct and apply said negative pulse to a first path in said second relay,.said first path in said second relay being initially conducting, to change conductivity to the second path in said second relay, means connected to said rst ypath in said second relay to beautomatically energized when said first path in said second relay is `nonconductng to apply a negative potential to said second path in said second relay after a prede'- termined interval to change conductivity. back to said first path in said second relay; and means connected to be energized to produce a voltage pulse when either path in said first relay or said secon-d path in said second relay ceases to conduct.

6. A pulse group system of communication, comprising two uli-symmetrical conductive paths whereof one is initially open-circuited, the unbalance being such that said one path becomes conducting when the circuit is closed, including means in each path to produce `a negative pulse at initiation of conduction in either path; first and second locked relays each having two symmeti-ical conductive paths, each said symmetrical path including means to produce and apply a potential due to current iiow to hold the other path in the same relay non-conducting, means connecting said one unsymmetrical path to trip said first relay when said one symmetrical path is closed; timed pulse-producing means connected to be operative while said first relay is tripped and connected to trip said second relay, then f reset said second relay; means connecting said second relay to said first relay to reset said first relay when said second relay is reset, means con:- nected to said first relay to produce a positive output pulse when said first relay is tripped, means connected to said second relay to produce a positive output pulse when said second relay-is tripped and also when it is reset; means connected to trip both said relays when said one symmetrical path is re-opened, said timing pulse 75 meansV then resetting both relays, means"topra- 9 duce a positive output pulse when said relays are both tripped and means to produce another positive output pulse when both said relays are'reset.

7. A pulse group system of communication, comprising two unsymnietrical conductive paths whereof one is initially open-circuited, the unbalance being such that said one path becomes conducting when the circuit is closed, including means in each path to produce a pulse at initiation of conduction in either path; first and second locked relays each having two symmetrical conductive paths, each said symmetrical path including means to produce and apply a potentia1 due to current flow to hold the other path in the same relay non-conducting, means connecting said one unsymmetrical path to trip said first relay when said one symmetrical path is closed; timed pulse-producing means connected to be operative while said rst relay is tripped and connected to trip said second relay, then reset said second relay; means connecting said second relay to said rst relay to reset said rst relay when said second relay is reset, means connected to said first relay to produce an output pulse when said first relay is tripped, means connected to said second relay to produce an output pulse when said second relay is tripped and also when it is reset; means connected to trip both said relays when said one symmetrical path is re-opened, said timing pulse means then resetting both relays, means to produce an output pulse when said relays are both tripped and means to produce another output pulse when both said relays are reset.

8. A pulse group system of communication, comprising two unsymmetrical conductive paths whereof one is initially open-circuited, the unbalance being such, that said one path' becomes conducting when the circuit is closed, including means in each path to produce a negative pulse at initiation of conduction in either path; first and second locked relays each having tw'symmetrical conductive paths, each said symmetrical path including means. to produce and apply a potential due to current flow to hold the other path in the same relay non-conducting, means connecting said one unsymmetrical path to trip said rst relay When said one symmetrical path isfclosed; means connected to be operative while said rst relay is tripped and connected to trip said second relay, then reset said second relay; means connecting said second relay to said rst relayA to reset said first relay when said second relay is reset, means connected to said irst relay to produce an output pulse when said first relay is tripped, means connected to said second relay to produce an output pulse when said second relay is tripped and also when it is reset; means connected to trip both said relays when said one symmetrical path is re-opened, said means operative when said rst relay is tripped then resetting both relays, means to produce an output pulse when said relays are both tripped and means to produce another output pulse when both said relays are reset. V

9. A receiver responsive to groups of pulses, comprising first and second locked relays, each said relay including two tubes each of which has an anode, a cathode, and at least two grids; a common anode supply, a respective anode resistor connecting each said anode to said supply, a resistor and a capacitor in parallel connecting the anode of eachsaid tube to one grid of the other tube in the same relay; a gaseous discharge device and a reset capacitor in parallel,

a timing resistor connecting said device and said reset capacitor to the anode of a first tube in said first relay to charge said capacitor when said relay is tripped; a tube having a grid, a cathode and an anode interposed between said relays, means to block said interposed tube, a resistor connecting the anode of said interposed tube to said supply, a capacitor coupling the anode of4 said interposed tube to another grid of the rst tube of said second relay; a respective capacitor coupling the anode of the second tube in said rst relay to the grid of said interposed tube and to another grid of the second tube in said second relay to trip said second relay, when said first relay is reset; an output tube having a cathode, a grid and an anode, a resistor connecting the anode of said output tube to said supply, means connecting the grid of said output tube to said one grid of .the iirst tube in said second relay to hold said output tube non-conducting when theiirst tube in said second relay is conducting, means to apply to the grid of the output tube an audio signal of insuflicient strength to render said output tube conducting when the first tube of the second relay is conducting, an output lead coupled to the anode of said output tube; an input circuit coupled to another grid of each tube in said first relay, and means coupling said reset capacitor to the grid of said interposed tube and to another grid in the second tube of said rst relay to reset said first relay, which Yresets said second relay and terminates the audio out-v put.

10. A pulse group system of communication,y

comprising means as set forth in claim 5 in com` bination with receiving means which comprises first and second locked relays each havingltwd symmetrical conductive paths, each saidrpath including means to produce` and apply alpe-'- tential due to current ow to hold the other path in the same relay non-conducting, input (means connected to said first relay to trip orto :reset: said'rst relay, depending upon which pathA isconducting; timed pulse producing meanscon-. nected to one path in saidfirst relay to be opera-z tive while said rst relay is tripped, means con-` trolled by thesecond path in said first relay to trip said second relay, when said first relay is reset, signal output means controlled by said second relay to operate while said second relay istripped, and means connecting the second path*V in said first relay with the second pathv in` said: second relay whereby when said first relay'is` tripped by a pulse while said signal output is; operating a reset pulse will be applied from said.- second path of said rst relay to reset said second relay and thereafter said timed pulse mean functions to reset said rst relay.

11. In a .pulse group system of communication, receiving means comprising rst and second locked relays each having two symmetrical conductive paths, each said path including means to rproduce and apply a potential due to Vcurrent flow to hold the other path in the same relay non-conducting, input means connected to said rs't relay to trip or to reset said flrstrelay,v depending upon which path is conducting; timed pulse producing means connected to one path in said rst relay to be operative while said rstj relay is tripped, means controlled by the second Dath in said flrstrelay to trip said second relay; when said rst relay is reset, signal output means controlled by said second relay to operate while said second relay is tripped, and means connecting the second path in said rst relay with the second path in saidl secondrelay.

aitcivr 11j whereby whenv said first relay is tripped by a pulsel while said signal output is operating a reset pulse will be Vapplied from said second path osaidfirst relay to reset'said second relay and thereafter'said timed pulse means functions to reset'said first relay.

l2; Pulse group signal-ling means, comprising rst'. and second interconnected and functionally dependent circuits, one said rst or second circuits being initially open and the other conducting;` third and fourth functionally dependent circuits interconnected to hold either third or fourth circuit non-conducting whenV the other conducts, one of said third or fourth .circuits being initially conducting; means connecting said initially open first or second circuit to said initially conducting third or fourth circuit to change the conductivity condition in said third and fourth when said first or second initially open circuit is closed; means connected to said initially conducting third or fourth circuit to produce a pulse a predetermined time after interruption offconduction in said initially conducting third or fourth circuit; and. to apply such pulse to the initially non-conducting third or fourth circuit to change conductivity back to said initially conducting third or fourth circuit, and means connected to each of said rst and second circuits and to said initially non-conducting third or' fourth circuit to produce a pulse upon interruption of conductivity in any respective one oi these three circuits.

13. A pulse group signalling system, comprisingapparatus as set'forth in claim l2 inV combination with .receiving'means which comprises a rst anda second pair of functionally dependent circuits,` the circuitsiin each pair being inter.- connectedto holdeither. circuit in a pair non.- conducting'when'; the interconnected circuit is conducting, onecircuit in eaclrpair being initiallyconducting;` the other; circuit in. each pair be'- ingfinitially non-conducting, a timed pulse pro.- ducing'device connected across said one circuit insaidrstpair'and to the` othencircuit in. said nrstrpairto Vchange conductivity vbaci:4 to said one circuitwhen saidone circuit insaid first pair has beenlnon-conducting for a` predetermined time interval; commoninput means connected to both circuitslin' said rst pairwl'iereby a negative pulse on saidinput will change conductivity from the thenconducting` circuit to the then non-conductingifcircuit; means'connected to said other circuitin; said .first pairto produce a negative pulse andapply the' same to said one circuit in said secondlpar. when conduction in said other circuitfof said nrst pair is interrupted, means connected to said other circuit in said rst pair to apply a negative pulse to said other circuit in saidsecond pair when conduction is initiated in said other circuit of said iirst pair; an output tube. connected to said one circuit in said secondLpairto be held conducting only when said cnet-circuit in said second. pair is non-conducting; arroutput connection to said.` tube, andmeans to'apply" an audio signal. to said. tube to. appear inzsaid output'onlyV when said tubeV is held condiluting A as aforesaid.

14'. Pulse group signal receiving means, comprisingarstand a second pair offunctionally dependent circuits, the circuits in each pair beingiinterconnected to hold either circuit in a pair non-conducting when the interconnected. circuit isi'conducting, on'ecircuitiin eachpair'beingin.- itially conducting; a.` timed pulse'producingdevice connected across. said one circuit in said iirstlpai-r andV toi theother circuitinsaid nrst pair toreset said. rst pair Ywhen said iirstrpair has'been tripped for a predetermined time iii-- terval; common input means. connected to. bothv circuits in' said` iirst4 pair whereby a. negative pulseon said input. will change conductivityI from the. then conducting circuit to the then nonconducti'ng' circuit; means". connected. to said othercircuit in said first pair to produce a negative; pulse and apply the same. to said one circuit in" said secondlpairwhen conduction in said other circuit. of said. first pairv is interrupted, means.` connected. to said. other. circuit. in saidy first nairtoapplyl a negativepulse to: said other circuit in. said second. pair when. conduction. is initiatedin said other circuit. of said first pair; anoutput tube connectedto. said one circuit in said second pair lto be held conducting only when said. one circuit in said second pair. is nonconducting, anV output connection. to said tube, and means to apply an audio signal to said tube to appear in said output only when said tube is held conducting as aforesaid.

l5. Pulse group signal receiving means, comprising a iirst and a second pair of functionally dependent circuits, the circuits in each pair being interconnected. to hold either circuit in a pair non-conducting when the interconnected circuit is conducting, one circuit in each pair being initially conducting; means to reset said rst pair when said rst pair. has been tripped for a predetermined time interval; common input. means connectedv to both circuits in said nrst pair whereby a negative pulse on said. input will change conductivity from the then conducting circuit to the then non-conducting circuit; means, connected to said other circuit in said first pair` to produce a negative pulse and apply the same to trip said second' pair when conduction in said other circuit of said first pair is interrupted; meansconnected to said other circuit in said i'lrst pair to apply a negativepulse to reset' said. second pairwhen conduction; is initiated in said other circuit of said first pair; and means connected to said second pair to produce a discernible output signal onlyywhen said second pair is tripped.

16. Apparatus as set forth in claim 12-, in combination' with receiving means responsive to a pair' of received pulses to initiate a discernible signal and to a single pulse to terminate said f signal.

17. Apparatus as set forth in claim 12, in combination with receiving means responsive to a' predetermined number of received pulses toinitiate a discernible signal and to a number of subsequently receivedv pulses to terminate said said timer subsequently resetting saidsecond re'- lay and meanscoupling tosaidfirst relay to reset the same responsively to resetting the second relay. Y

19. A receiver as set forth in claim` 18 further including anaudio channel, and meansfor delivering anY audio. signal to.. said channel controlledby said secondrelay to be Voperativefvvhile` said second relay is` in trippedcondition.

20. InV a communication System Vof the mark-- space typewherein theleading and trailingedges of the mark signals are delineated by first and second signal components respectively, signal receiving means responsive to a iirst received sisnal to initiate a discernible signal and to a subsequently received second signal to terminate the discernible signal, one of the received signals comprising a group of impulses, and the other of said signals comprising a diiierent number of impulses.

21. In a communication system of the markspace type wherein the leading and trailing edges of the mark signals are delineated by first and second signal components respectively, signal receiving means responsive to a first received signal to initiate a discernible signal and to a subsequently received second signal to terminate the discernible signal, one of the received signals comprising a single impulse, and the other of said signals comprising a group of impulses.

22. In a pulse signal communication system, transmitting apparatus comprising, in combination, a pulse generator, a switch, and circuit means controlling said impulse generator responsive to the opening of said switch to effect generation of a iirst pulsed signal and responsive to the closing of said switch to generate a second pulsed signal including a diierent number of pulses from the iirst pulsed signal.

23. A transmission system comprising a pulse generator, a switch, circuit means controlling saidA impulse generator responsive to the closing of said switch to effect generation of a first pulsed signal and responsive to the opening of the switch to generate a second pulsed signal having a characteristics difference from the first pulsed signal, and receiver means receiving said pulsed signals responsive to one of said pulsed signals to initiate 'a discernible signal and responsive to the other of said signals to terminate the discernible signal.

24. In combination, a trigger' circuit having a stable condition and an unstable condition and comprising a pair o vacuum tubes, a condenser connected between the grid of one tube and the anode of the other tube, la condenser shunted by a resistor connected between the anode of said one tube and the grid of said other tube, means connected to said trigger circuit for normally maintaining conduction in one of said tubes and non-conduction in the other, a second trigger circuit having two states of stability and including a pair of vacuum tubes, similar coupling networks connecting the grid of each tube of the second trigger circuit to the anode of the other, a couplingrcircuit 'capable of passing pulses of only one polarity connecting the two trigger circuits in cascade relation, coupling means between the second tube of said second trigger circuit and the second tube of the rst trigger circuit and means for applying initiating voltage 'pulse to the iirst trigger circuit of such polarity and magnitude as to change the condition of the iirst trigger circuit.

25. In combination, first and second trigger circuits each having a pair of vacuum tubes, connections cross-coupling the grids and anodes of the tubes of each trigger circuit, means connected to the first trigger circuit for endowing the same with a stable state and an unstable state, a diierentiator circuit of a reactance and a resistor in series coupled between one of the anodes of the rst trigger circuit and ground, a coupling vacuum tube having its grid connected to the junction of said reactance and resistor and having its anode coupled to the grid of one of the tubes of' said second trigger circuit, means for biasing said coupling vacuum tube to cut off` dur-- ing the stable condition of said first trigger cir.

cuit, coupling means between the second tube of said second trigger circuit and the second tube of the rst trigger circuit and means for deriving from said second trigger circuit a voltage developed thereby.

26. In combination, first and second vacuum tube trigger circuits for producing fiat top pulses, means connected to the rst trigger circuit for endowing the same with a stable state and an unstable state, a connection for applying an initiating -voltage pulse signal to said iirst trigger circuit of such polarity and magnitude as to change the condition of said iirst trigger circuit, and means coupling said trigger circuits together in such manner that there is introduced a time lag between the time of occurrence of said initiating pulse and the operation of said second trigger circuit, said means including a condenser and a vacuum tube in series therewith, said vacuum tube being biased to pass pulses of only one polarity and coupling means between the second tube of said second trigger circuit and the second tube of the iirst trigger circuit.

27. In a communication system of the type in.

which signal characteristics are represented by a series of rst impulses modulated in duration to represent the signal characteristics; an arrangement for reducing the disturbing effects of interfering impulses comprising, means for producing from each of said iirst impulses a group' of at least three short duration indicating impulses, at least two of said group of indicating impulses being spaced vvapart by a time interval which is short compared'to the duration of the first impulses, the remaining impulses of said group being spaced from :said two by an interval governed by the duration of said iirst impulses, receiver means for receiving said indicating impulses, and discriminator means in said receiver means for discriminating between impulse groups having a number and time spacing other than that produced by the first mentioned means.

28. A communication system according to claim 27 further comprising translator means for deriving the modulating signal from said received indicating impulses.

29. A method of communicating by continuous wave radio telegraphy signals of the mark-space type, comprising the steps of converting the mark signals into pulse signals oi substantially constant duration and spaced in time corresponding .to the duration of said mark signals, the pulse signals corresponding to the initiation of said mark signals being different in number from those corresponding the termination thereof, transmitting said pulse signals through space, receiving said signals, and converting said pulse signals back to said mark signals thereby reproducing said telegraphy signals.

30. A method of communicating by continuous wave radio telegraphy signals of the mark-space type, comprising the steps of converting the mark signals into pulse signals comprising a pair of pulses corresponding to the initiation of said mark signals and a single pulse corresponding to the termination of said mark signals, transmitting said pulse signals through space, receiving said pulse signals, and converting said received pulse signals back to said mark signals therebi7 reproducing said telegraphy signals.

31. Apparatus for communicating by means of continuous wave radio telegraphy signals of the marin-space type, comprising'agaseousdischarge tube device to `convert the marksignals into pulse signals of substantially constant duration and spaced in time corresponding to the durationoi said mark signals, the pulse signals correspond.- ing to the initiationv of said mark; signals being different in number from those corresponding to the termination thereof, means to transmit said pulse signals through space, meansl to receive said transmitted pulse signals, and a second discharge tube device to convert said pulse signals back to said mark signais thereby to reproduce said telegraphy signals.

32. Apparatus for communicatingby'meansof continuous wave radio telegraphy signals ofthe mark-space type, comprising a gaseous discharge tube device to convert the mark signals into pulse signals comprising a pair of pulses corresponding to the initiation of the mark signals and a single pulse corresponding to the termination of said mark signals, means to transmit said pulse signals through space, means to receive said transmitted pulse signals, and a second discharge tube device to convert said pulse signals back to said mark signals thereby to reproduce said telegraphy signals.

33. A pulse generating means comprising first and second trigger circuits each. having two conductive paths, means for normally maintaining conduction in a particular path of. eachof said trigger circuits, means for changing the state of conduction of said iirst trigger circuit, means for changing the state of conduction of said second trigger circuit, both of said trigger circuits being coupled to acommon output signal channel to initiate therein output signal pulses upon changes in saidstates of conduction.

34. A pulse generating device comprising first and second trigger circuits each having two conductive paths, means for normally maintaining conduction. in a particular path of each of said trigger circuits, means for changing the state of conduction of said first trigger circuit, means responsive to the changing of the state of conduction..of said first trigger circuit for changing the state of conduction of said second trigger circuit, bothV of said trigger circuits being coupled to a common output signal channel to initiate therein output signal pulses upon changes in said states of conduction.

35. In combination, iirst, second and third trigger circuits each having rst and second. conductive paths, at least one input and one output means, means coupling an output means of said iirst trigger circuitto an input means of both of said second and third trigger circuits to thereby enable a change in the state of conduction of said first trigger circuit to affect the states of conduction of said second and third trigger cirsaid third trigger circuit .to/.an inputmeansof.

said-1 second.V trigger circuit to thereby enables` change in the state of conduction of said third trigger circuit to ailect the state of condtionof, said second trigger circuit.

36. In a pulse. signal communicationsystem, transmitting apparatus comprising in. combina tion, iirst means including a pulse generator for producing pulses for conveying intelligence, and a secondmeans including a second pulse. generatorv controlled by said first generator to producepulse groups at the beginning and at. theendof each of said intelligence conveying, pulses, said beginning and, saidend pulse groups having different numbers of pulses therein.

37. In a communication system includingthe` transmitting apparatus defined in claim 36, signal receiving means responsive to a received group of pulses to initiate a discernibleV signal and to a subsequently received groupsof pulses.

to terminate said signal.

CLAUD E. CLEETON.-

REFERENCES CTED The following references are oi record inthele of this patent:

UNITED STATES PATENTS Number Name Date.A

1,616,186 Harlow Feb. 1, 1927 1,702,423 Wensley Feb; 19 1929 1,765,538 Nelson .June 24, 1930 1,864,303 Hallden June 21, 1932- 1,979,484 Mathes Nov. 6, 1934 1,997,683 Hennig Apr.. 16,1935 2,052,677 Thompson et al. Sept. 1., 1936 2,061,734 Kell Nov. 241936. 2,118,156 Burton May 24, 1938 2,154,492 Clough Apr. 18,- 1939 2,158,285 Koch May 16 1939 2,265,290 Knick Dec. 9, 1941 2,272,070 Reeves Feb. 3, 1942 FOREIGN PATENTS Number Country Date 49,159 France Aug. ,22,` 1938 (1st addition to No. 833,929) 333,929 France Aug. 1, 1938v OTHER REFERENCES Physical Review, vol. 53, 1938, Multivibrator Geiger Counter Circuit, by Getting, p. 103.. v

Review of Scientific Instruments, vol.. 9, March. 1938, A Triode Vacuum Tube Scale-of-Two Circuits, by Lifschutz et al., pages 83 to 89.

Review of Scientific Instruments, vol. 10, January 1939, A Complete Geiger-Mller Counting System, by Lifschutz, pages 21 to 26. 

